summaryrefslogtreecommitdiffstats
path: root/kernel/drivers/hwmon/lm75.h
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/drivers/hwmon/lm75.h')
-rw-r--r--kernel/drivers/hwmon/lm75.h49
1 files changed, 49 insertions, 0 deletions
diff --git a/kernel/drivers/hwmon/lm75.h b/kernel/drivers/hwmon/lm75.h
new file mode 100644
index 000000000..5cde94e56
--- /dev/null
+++ b/kernel/drivers/hwmon/lm75.h
@@ -0,0 +1,49 @@
+/*
+ lm75.h - Part of lm_sensors, Linux kernel modules for hardware
+ monitoring
+ Copyright (c) 2003 Mark M. Hoffman <mhoffman@lightlink.com>
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+/*
+ This file contains common code for encoding/decoding LM75 type
+ temperature readings, which are emulated by many of the chips
+ we support. As the user is unlikely to load more than one driver
+ which contains this code, we don't worry about the wasted space.
+*/
+
+#include <linux/kernel.h>
+
+/* straight from the datasheet */
+#define LM75_TEMP_MIN (-55000)
+#define LM75_TEMP_MAX 125000
+#define LM75_SHUTDOWN 0x01
+
+/* TEMP: 0.001C/bit (-55C to +125C)
+ REG: (0.5C/bit, two's complement) << 7 */
+static inline u16 LM75_TEMP_TO_REG(long temp)
+{
+ int ntemp = clamp_val(temp, LM75_TEMP_MIN, LM75_TEMP_MAX);
+ ntemp += (ntemp < 0 ? -250 : 250);
+ return (u16)((ntemp / 500) << 7);
+}
+
+static inline int LM75_TEMP_FROM_REG(u16 reg)
+{
+ /* use integer division instead of equivalent right shift to
+ guarantee arithmetic shift and preserve the sign */
+ return ((s16)reg / 128) * 500;
+}